35% of people eat in "subsidized" onsite or on-campus cafeterias and foodcourts. This tends to include Microsoft, Amazon, and Apple.
15% of people will go to local area eateries, grab their food to-go, then return to the site to keep their time offsite to a minimum, then eat at their desk. Personal orders to Grubhub, etc. fall in this category, and this category is growing.
15% of people will go to area eateries, dine in. These tend to be upper management, as it's easier to argue that it's a working lunch.
15% skip all meals or snack on food brought from home.
If you're making $80/hr., a one-hour lunch break unpaid makes your lunch about $100, so it's a very expensive decision to take a continental-style lunch offsite.
If you think as a big part of your job, your employer derives a free benefit from your time spent offsite. If you lose focus by spending time offsite, your employer derives an expensive benefit by feeding you free lunch.
1 hour lunch break is often encouraged by employers. Working as a freelancer I work an "extra" hour, because of my lunch break. So do the employees here.